A 4×4 5-6GHz CMOS Wi-Fi Transceiver Front-End for Fiber-to-the-Room with Analog Beamforming Achieving 27dBm 1024 QAM MCS11 EIRP and −45dB EVM Floor

Commercially launched by more than 100 world-wide operators with a compound annual growth rate (CAGR) of ~30%, Fiber-To-the-Room (FTTR) is becoming the mainstream home broadband service that provides gigabit bandwidth and reliable transmission covering everywhere at home and office, by extending the all-optical networks to each room with multiplied access points (APs) [1], as shown in Fig. 1 where omnidirectional radiation (OR) architecture(OR-FTTR) [2]–[4] with conventional RF front-end module (FEM) has been employed and leads to coverage overlap, severe signal interference and unnecessary power consumption, affecting the user experience. Digital beamforming however is unrealistic due to the high-cost and high-complexity base-band design. To address the above issues, this paper proposes the analog beamforming architecture for FTTR (BF-FTTR), which greatly alleviates signal interference by enabling directional radiation and fine gain control. In addition, owing to the higher gain of directional antenna arrays, the effective isotropic radiated power (EIRP) of BF-FTTR is enhanced even with lower output power compared to the OR-FTTR, achieving better linearity and lower power consumption, and alleviating the requirement for digital pre-distortion (DPD).